Tom Parsons
I conduct research aimed at improving our ability to forecast hazardous events like earthquakes and tsunamis. Specifically, I study how earthquakes trigger others, how crustal movements cause earthquake stresses, and how to convert geologic observations of earthquake and tsunami processes into quantitative forecasts of use to planners, insurers, and builders.
Professional Experience
1994-Present: Research Geophysicist, U. S. Geological Survey, Moffett Field, CA
1992-1994: National Research Council Postdoctoral Fellow
Education and Certifications
1992 – Ph.D. in Geophysics, Stanford University
1990 – M.S. in Geophysics, Stanford University
1988 – B.S. in Applied Geophysics, UCLA
Affiliations and Memberships*
Editor, AGU Advances, 2019-2022
Member: Executive Committee, Council of Senior Science Advisors (COSSA), 2015-present
Editor in Chief, Journal of Geophysical Research, Solid Earth, 2009-2015
Editor in Chief, Tectonophysics, 2007-2009
Editorial Board, Tectonophysics, 2005-2007
Editorial Board, Geology, 1995-2000, 2005-2008
Member: Executive Committee, Working Group on California Earthquake Probabilities 2005-2014
Member: SCEC Planning Committee, 2007-2009
Honors and Awards
Senior Scientist (ST): 1/15
Fellow American Geophysical Union, Elected 1/12
Fulbright Mutual Educational Exchange Grant USA-Greece: 2007-2008
Alumni Pillar of Achievement: Golden West College Outstanding Alumni Award (10/07)
Fellow Geological Society of America, Elected 10/97
Shoemaker Communication Award (10/00)
National Association of Government Communicators Gold Screen Award (12/00)
National Research Council Post-Doctoral Fellow (8/92)
Science and Products
Filter Total Items: 120
Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3) Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that...
Authors
Edward H. Field, Glenn P. Biasi, Peter Bird, Timothy E. Dawson, Karen R. Felzer, David A. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin Milner, Morgan T. Page, Thomas E. Parsons, Peter Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
The global aftershock zone The global aftershock zone
The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often...
Authors
Thomas E. Parsons, Margaret Segou, Warner Marzocchi
Undersampling power-law size distributions: effect on the assessment of extreme natural hazards Undersampling power-law size distributions: effect on the assessment of extreme natural hazards
The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these...
Authors
Eric L. Geist, Thomas E. Parsons
Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez
Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine...
Authors
Thomas E. Parsons, Eric L. Geist, Holly F. Ryan, Homa J. Lee, Peter J. Haeussler, Patrick Lynett, Patrick E. Hart, Ray W. Sliter, Emily C. Roland
Stress, distance, magnitude, and clustering influences on the success or failure of an aftershock forecast: the 2013 M 6.6 Lushan earthquake and other examples Stress, distance, magnitude, and clustering influences on the success or failure of an aftershock forecast: the 2013 M 6.6 Lushan earthquake and other examples
No abstract available.
Authors
Thomas E. Parsons, M. Segou
New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords
The 1964 Alaska M w 9.2 earthquake triggered numerous submarine slope failures in fjords of southern Alaska. These failures generated local tsunamis, such as at Whittier, where they inundated the town within 4 min of the beginning of shaking. Run-up was up to 32 m, with 13 casualties. We collected new multibeam bathymetry and high-resolution sparker seismic data in Passage Canal, and we...
Authors
Peter J. Haeussler, Thomas E. Parsons, David P. Finlayson, Patrick J. Hart, Jason D. Chaytor, Holly F. Ryan, Homa J. Lee, Keith A. Labay, Andrew Peterson, Lee Liberty
Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014 M=6.0 West Napa earthquake Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014 M=6.0 West Napa earthquake
We calculate stress changes resulting from the M = 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because...
Authors
Thomas E. Parsons, Margaret Segou, Volkan Sevilgen, Kevin Milner, Edward H. Field, Shinji Toda, Ross S. Stein
Uniform California earthquake rupture forecast, version 3 (UCERF3): the time-independent model Uniform California earthquake rupture forecast, version 3 (UCERF3): the time-independent model
In this report we present the time-independent component of the Uniform California Earthquake Rupture Forecast, Version 3 (UCERF3), which provides authoritative estimates of the magnitude, location, and time-averaged frequency of potentially damaging earthquakes in California. The primary achievements have been to relax fault segmentation assumptions and to include multifault ruptures...
Authors
Edward H. Field, Glenn P. Biasi, Peter Bird, Timothy E. Dawson, Karen R. Felzer, David D. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin R. Milner, Morgan T. Page, Thomas Parsons, Peter M. Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
Estimation of submarine mass failure probability from a sequence of deposits with age dates Estimation of submarine mass failure probability from a sequence of deposits with age dates
The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from...
Authors
Eric L. Geist, Jason D. Chaytor, Thomas E. Parsons, Uri S. ten Brink
Diffuse Pacific-North American plate boundary: 1000 km of dextral shear inferred from modeling geodetic data Diffuse Pacific-North American plate boundary: 1000 km of dextral shear inferred from modeling geodetic data
Geodetic measurements tell us that the eastern part of the Basin and Range Province expands in an east-west direction relative to stable North America, whereas the western part of the province moves to the northwest. We develop three-dimensional finite element representations of the western United States lithosphere in an effort to understand the global positioning system (GPS) signal...
Authors
T. Parsons, W. Thatcher
Absence of remotely triggered large earthquakes beyond the mainshock region Absence of remotely triggered large earthquakes beyond the mainshock region
Large earthquakes are known to trigger earthquakes elsewhere. Damaging large aftershocks occur close to the mainshock and microearthquakes are triggered by passing seismic waves at significant distances from the mainshock. It is unclear, however, whether bigger, more damaging earthquakes are routinely triggered at distances far from the mainshock, heightening the global seismic hazard...
Authors
T. Parsons, A.A. Velasco
No correlation between Anderson Reservoir stage level and underlying Calaveras fault seismicity despite calculated differential stress increases No correlation between Anderson Reservoir stage level and underlying Calaveras fault seismicity despite calculated differential stress increases
Concerns have been raised that stresses from reservoir impoundment may trigger damaging earthquakes because rate changes have been associated with reservoir impoundment or stage-level changes globally. Here, the idea is tested blindly using Anderson Reservoir, which lies atop the seismically active Calaveras fault. The only knowledge held by the author going into the study was the...
Authors
T. Parsons
Non-USGS Publications**
1992, by Parsons, T. et al., Department of Geophysics, Stanford University
1992, by Parsons, T., et al., Department of Geophysics, Stanford University
1991, by Howie, J.M., et al., Department of Geophysics, Stanford University
1991, by Parsons, T., and Thompson, G.A., Department of Geophysics, Stanford University
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 120
Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3) Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)
The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that...
Authors
Edward H. Field, Glenn P. Biasi, Peter Bird, Timothy E. Dawson, Karen R. Felzer, David A. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin Milner, Morgan T. Page, Thomas E. Parsons, Peter Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
The global aftershock zone The global aftershock zone
The aftershock zone of each large (M ≥ 7) earthquake extends throughout the shallows of planet Earth. Most aftershocks cluster near the mainshock rupture, but earthquakes send out shivers in the form of seismic waves, and these temporary distortions are large enough to trigger other earthquakes at global range. The aftershocks that happen at great distance from their mainshock are often...
Authors
Thomas E. Parsons, Margaret Segou, Warner Marzocchi
Undersampling power-law size distributions: effect on the assessment of extreme natural hazards Undersampling power-law size distributions: effect on the assessment of extreme natural hazards
The effect of undersampling on estimating the size of extreme natural hazards from historical data is examined. Tests using synthetic catalogs indicate that the tail of an empirical size distribution sampled from a pure Pareto probability distribution can range from having one-to-several unusually large events to appearing depleted, relative to the parent distribution. Both of these...
Authors
Eric L. Geist, Thomas E. Parsons
Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez Source and progression of a submarine landslide and tsunami: The 1964 Great Alaska earthquake at Valdez
Like many subduction zone earthquakes, the deadliest aspects of the 1964 M = 9.2 Alaska earthquake were the tsunamis it caused. The worst of these were generated by local submarine landslides induced by the earthquake. These caused high runups, engulfing several coastal towns in Prince William Sound. In this paper, we study one of these cases in detail, the Port Valdez submarine...
Authors
Thomas E. Parsons, Eric L. Geist, Holly F. Ryan, Homa J. Lee, Peter J. Haeussler, Patrick Lynett, Patrick E. Hart, Ray W. Sliter, Emily C. Roland
Stress, distance, magnitude, and clustering influences on the success or failure of an aftershock forecast: the 2013 M 6.6 Lushan earthquake and other examples Stress, distance, magnitude, and clustering influences on the success or failure of an aftershock forecast: the 2013 M 6.6 Lushan earthquake and other examples
No abstract available.
Authors
Thomas E. Parsons, M. Segou
New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords New imaging of submarine landslides from the 1964 earthquake near Whittier, Alaska, and a comparison to failures in other Alaskan fjords
The 1964 Alaska M w 9.2 earthquake triggered numerous submarine slope failures in fjords of southern Alaska. These failures generated local tsunamis, such as at Whittier, where they inundated the town within 4 min of the beginning of shaking. Run-up was up to 32 m, with 13 casualties. We collected new multibeam bathymetry and high-resolution sparker seismic data in Passage Canal, and we...
Authors
Peter J. Haeussler, Thomas E. Parsons, David P. Finlayson, Patrick J. Hart, Jason D. Chaytor, Holly F. Ryan, Homa J. Lee, Keith A. Labay, Andrew Peterson, Lee Liberty
Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014 M=6.0 West Napa earthquake Stress-based aftershock forecasts made within 24h post mainshock: Expected north San Francisco Bay area seismicity changes after the 2014 M=6.0 West Napa earthquake
We calculate stress changes resulting from the M = 6.0 West Napa earthquake on north San Francisco Bay area faults. The earthquake ruptured within a series of long faults that pose significant hazard to the Bay area, and we are thus concerned with potential increases in the probability of a large earthquake through stress transfer. We conduct this exercise as a prospective test because...
Authors
Thomas E. Parsons, Margaret Segou, Volkan Sevilgen, Kevin Milner, Edward H. Field, Shinji Toda, Ross S. Stein
Uniform California earthquake rupture forecast, version 3 (UCERF3): the time-independent model Uniform California earthquake rupture forecast, version 3 (UCERF3): the time-independent model
In this report we present the time-independent component of the Uniform California Earthquake Rupture Forecast, Version 3 (UCERF3), which provides authoritative estimates of the magnitude, location, and time-averaged frequency of potentially damaging earthquakes in California. The primary achievements have been to relax fault segmentation assumptions and to include multifault ruptures...
Authors
Edward H. Field, Glenn P. Biasi, Peter Bird, Timothy E. Dawson, Karen R. Felzer, David D. Jackson, Kaj M. Johnson, Thomas H. Jordan, Christopher Madden, Andrew J. Michael, Kevin R. Milner, Morgan T. Page, Thomas Parsons, Peter M. Powers, Bruce E. Shaw, Wayne R. Thatcher, Ray J. Weldon, Yuehua Zeng
Estimation of submarine mass failure probability from a sequence of deposits with age dates Estimation of submarine mass failure probability from a sequence of deposits with age dates
The empirical probability of submarine mass failure is quantified from a sequence of dated mass-transport deposits. Several different techniques are described to estimate the parameters for a suite of candidate probability models. The techniques, previously developed for analyzing paleoseismic data, include maximum likelihood and Type II (Bayesian) maximum likelihood methods derived from...
Authors
Eric L. Geist, Jason D. Chaytor, Thomas E. Parsons, Uri S. ten Brink
Diffuse Pacific-North American plate boundary: 1000 km of dextral shear inferred from modeling geodetic data Diffuse Pacific-North American plate boundary: 1000 km of dextral shear inferred from modeling geodetic data
Geodetic measurements tell us that the eastern part of the Basin and Range Province expands in an east-west direction relative to stable North America, whereas the western part of the province moves to the northwest. We develop three-dimensional finite element representations of the western United States lithosphere in an effort to understand the global positioning system (GPS) signal...
Authors
T. Parsons, W. Thatcher
Absence of remotely triggered large earthquakes beyond the mainshock region Absence of remotely triggered large earthquakes beyond the mainshock region
Large earthquakes are known to trigger earthquakes elsewhere. Damaging large aftershocks occur close to the mainshock and microearthquakes are triggered by passing seismic waves at significant distances from the mainshock. It is unclear, however, whether bigger, more damaging earthquakes are routinely triggered at distances far from the mainshock, heightening the global seismic hazard...
Authors
T. Parsons, A.A. Velasco
No correlation between Anderson Reservoir stage level and underlying Calaveras fault seismicity despite calculated differential stress increases No correlation between Anderson Reservoir stage level and underlying Calaveras fault seismicity despite calculated differential stress increases
Concerns have been raised that stresses from reservoir impoundment may trigger damaging earthquakes because rate changes have been associated with reservoir impoundment or stage-level changes globally. Here, the idea is tested blindly using Anderson Reservoir, which lies atop the seismically active Calaveras fault. The only knowledge held by the author going into the study was the...
Authors
T. Parsons
Non-USGS Publications**
1992, by Parsons, T. et al., Department of Geophysics, Stanford University
1992, by Parsons, T., et al., Department of Geophysics, Stanford University
1991, by Howie, J.M., et al., Department of Geophysics, Stanford University
1991, by Parsons, T., and Thompson, G.A., Department of Geophysics, Stanford University
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government